Hash functions operate by computing a value based on upon a larger set of data (e.g., a number representing a string of text). The resulting value, or hash, is typically much smaller than the larger number from which the hash is computed. A hash is reproducible, such that when the same input is processed by the same hash function, the same hash will result.
Hash functions often are implemented in hardware. This requires use of resources and/or area (e.g., of an integrated circuit) that are consumed by the hardware to implement the hash function.